A type of connector used to connect a single optical fiber cable (optical cable), with a plug-socket attached to a door of an external multi-port terminal box, installed overhead or underground and in which plug-sockets are connected the optic fibers of a network to be accessed by different users by means of said single optic fiber cables.
In the type of external application in question, the terminal box plug-sockets and the individual cable connectors shall be constructed to withstand stringent conditions of temperature, humidity, exposure to chemical agents and other adverse operating conditions, generally present in an outdoor installation exposed to the weather.
The connectors are customarily and previously attached to the end of a respective optical access cable, generally using specific tools, to enable the respective optic fiber to be connected to one of the optic fibers of the network by means of the simple plug into a terminal box plug-socket.
A known type of connector is described in the patent application BR 10 2014 016480 4, of the same applicant, being formed by a tubular inner body having a rear end securing one end of an optical cable, and one end prior to which a connecting bolt is attached to a plug-socket of a terminal box; a tubular housing surrounding and retaining the inner body; an anchoring means defined by a crimping tube, for anchoring the jacket and the pulling elements of the optical cable to the inner body.
In this type of connector, the crimping tube involves an extension of the traction elements placed over a portion of the inner body to be crimped in at least two regions axially spaced apart from each other and, together with the confronting portion of the elements, inwardly from an external circumferential recess of the inner body to penetrate the outer jacket of the optical cable anchoring both the jacket and pulling elements to the connector's inner body.
The connector described above requires the provision of the crimping tube and consequently, specific tools for carrying out said crimping operation, making it difficult or even impossible to mount such connector at the end of an optical cable in the field.
In addition to the above-mentioned limitation relating to the requirement for mounting tools installed at specific locations, this known connector also requires the provision of equipment to ensure the correct introduction of the bare optical fiber projecting from the end of the tube jacket, in the interior of the tubular internal body and also the engagement and retention of the bare optical fiber inside the connector bolt, avoiding possible solutions of continuity of transmission between the optical fiber and the bolt and also risks of damage in the assembly operation of the optic fiber on the connector.
Another known construction and facing a connector for optic fiber cable is described in WO2 013/129485. In this second construction, the connector also comprises a tubular inner body having a front end to which is attached a connecting bolt to a plug-outlet of a terminal box and a rear end into which a clamp configured to receive and lock the end of the jacket of a low friction optical cable to be adapted to the connector. Finishing and outer closure elements are usually provided around the inner body of the connector.
A first aspect related to the aforementioned field connector concerns the fact that it does not predict its adaptation to the end of circular optical cables and provided with multiple traction cables, generally in aramid, and its design is exclusively directed to the low friction cables.
In such field connectors, the inner body is provided with means for directing the bare optic fiber extension projecting from the end of the cable jacket to its subsequent engagement and retention within the connector bolt, this operation is done manually by the operator without requiring special tools.
The inner body further has an inspection window for enabling the operator to track the guided displacement of the bare optical fiber through the interior of the inner body towards the interior of the bolt at the time of engagement and retention of the clamp within the rearward end of the inner body.
However, in this prior construction the fiber jacket, defined by the acrylate coating (protective sheath of the individual optical fiber) is arranged along the interior of the inner body without any locking point with respect to the latter, being the only one between the optical cable and the inner body made by locking the cable jacket in the clamp and by locking the latter inside the rear end of the inner body of the connector. In this construction, the assembly defined by the bare optical fiber and the respective acrylate fiber jacket is only guided inside the inner body, becoming “loose” inside the latter, even after the bare optic fiber has been engaged and locked in the bolt. It should be noted that in this low friction cable, the pair of traction cables is sectioned at the end of the jacket, such traction cables not engaged by the optical cable locking the connector.
In this second connector of the prior art there is no locking of traction cables in relation to the inner body of the connector, it being evident that its design is exclusively intended for assembly in low friction cables subjected to tensile stresses relatively small, allowing the locking optical cable connector to be secured exclusively by locking the cable jacket without any locking of the pull cables to the connector body.
Thus, although the second construction described in WO 2013/129485 allows mounting the connector at the end of a low friction optical cable in the field, without the use of special tools, it has the drawbacks and limitations discussed above.